I am super excited about The Martian coming out this weekend. It looks awesome! I could gush a few thousand words for the movie, but I won’t. Instead, I’ll share some speculation. I was reading about the hard science aspects of the movie, and I got to wondering whether or not it will delve into how the stranded astronaut stayed cool on the surface of Mars. Basically, how would air conditioning The Martian work?
Air Conditioning The Martian
Space is cold. Okay, it’s not so much ‘cold’ as it completely lacks any kind of heat. That’s a problem NASA tackled a long time ago. They had to or any astronauts we sent into low-Earth orbit would freeze to death in a matter of minutes.
Which is bad.
Let’s get back to air conditioning The Martian. The astronauts sent to explore Mars would use the same HVAC tech NASA always has on the way to the Red Planet, but what about when they got to the surface? Would they need something really high tech or could one of our MrCool (quite terrestrial) air conditioners work?
The answer is kind of interesting.
Conventional Air Conditioning on Mars
Earth-based air conditioners work by sucking the heat out of your house and dumping it outside via what’s commonly known as the refrigeration cycle. Technically speaking, there’s no reason why the refrigeration cycle wouldn’t work on any planet with an atmosphere. An air conditioner exactly like the one you’ve got running inside your house could, in theory, run on an alien world.
It would not, however, do much good on Mars.
Air conditioning the Martian through conventional means is right out the window. The reason isn’t fundamental – it’s temperamental. Mars is really, really, really cold. Yes, the temperature on the Martian equator can get up to about 70 degrees on a summer day. That’s decently warm, and your air conditioner would work in that temperature range. Maybe even on Mars.
The problem would arise when night fell. The Martian atmosphere is about 100 times thinner than our own, so Mars doesn’t have much of a thermal blanket. Heat retention is not a thing there. Which means the regular nightly temperature even on the Martian equator can hit -100 degrees. Yeah, you wouldn’t need an air conditioner then, and if you tried to operate one it would immediately freeze.
An energy efficient heat pump wouldn’t work well either. There are heat pumps that can operate at around 0 degrees, but the HVAC industry has yet to build one to operate at -100. You might say there’s not a market for that yet.
But, who knows, maybe one day in the sort-of-near future, HVAC companies will be building air conditioners to keep you cool during your vacation to the Red Planet.
Not anytime soon though.